Excerpt from the Free System Distribution Guidelines:
A free system distribution must not steer users towards obtaining any nonfree
information for practical use, or encourage them to do so. The system should
have no repositories for nonfree software and no specific recipes for
installation of particular nonfree programs. Nor should the distribution
refer to third-party repositories that are not committed to only including
free software; even if they only have free software today, that may not be
true tomorrow. Programs in the system should not suggest installing nonfree
plugins, documentation, and so on.
https://www.gnu.org/distros/free-system-distribution-guidelines.html
You can install the .deb from Debian. You are on your own to check that the
Python modules you then install with python3-distutils are free software.
